Improvement in quality of life is accompanied with people's ever-increasing requirements for high-quality audio. Compared with mono audio, stereo audio provides sense of direction and sense of distribution of sound sources and can improve clarity and intelligibility of information, and is therefore highly favored by people.
Currently, there is a known technology for transmitting a stereo audio signal. An encoder converts a stereo signal into a mono audio signal and a parameter such as an ITD, separately encodes the mono audio signal and the parameter, and transmits an encoded mono audio signal and an encoded parameter to a decoder. After obtaining the mono audio signal, the decoder further restores the stereo signal according to the parameter such as the ITD. Therefore, low-bit and high-quality transmission of the stereo signal can be implemented.
In the foregoing technology, based on a sampling rate of a time-domain signal on mono audio, the encoder can determine a limiting value Tmax of an ITD parameter at the sampling rate, and therefore may perform searching and calculation subband by subband within a range [−Tmax, Tmax] based on a frequency-domain signal, to obtain the ITD parameter.
However, the foregoing relatively large search range causes a large calculation amount in a process of determining an ITD parameter in a frequency domain in other approaches. Consequently, a performance requirement for an encoder increases, and processing efficiency is affected.
Therefore, a technology is expected to be provided such that a calculation amount in a process of searching for and calculating an ITD parameter can be reduced while accuracy of the ITD parameter is ensured.